package com.hmdp.service.impl;

import cn.hutool.core.util.BooleanUtil;
import cn.hutool.core.util.StrUtil;
import cn.hutool.json.JSONObject;
import cn.hutool.json.JSONUtil;
import com.baomidou.mybatisplus.extension.plugins.pagination.Page;
import com.hmdp.dto.Result;
import com.hmdp.entity.Shop;
import com.hmdp.mapper.ShopMapper;
import com.hmdp.service.IShopService;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.hmdp.utils.CacheClient;
import com.hmdp.utils.RedisConstants;
import com.hmdp.utils.RedisData;
import com.hmdp.utils.SystemConstants;
import org.springframework.data.geo.Distance;
import org.springframework.data.geo.GeoResult;
import org.springframework.data.geo.GeoResults;
import org.springframework.data.redis.connection.RedisGeoCommands;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.data.redis.domain.geo.GeoReference;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

import javax.annotation.Resource;
import java.time.LocalDateTime;
import java.util.*;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.TimeUnit;

/**
 *  服务实现类
 */
@Service
public class ShopServiceImpl extends ServiceImpl<ShopMapper, Shop> implements IShopService {

    @Resource
    private StringRedisTemplate stringRedisTemplate;

    @Resource
    private CacheClient cacheClient;

    /**
     * 根据id查询商铺信息
     * @param id
     * @return
     */
    @Override
    public Result queryById(Long id) {
        //缓存穿透
        Shop shop = cacheClient.queryWithPassThrough(RedisConstants.CACHE_SHOP_KEY, id, Shop.class, this::getById, RedisConstants.CACHE_SHOP_TTL, TimeUnit.MINUTES);

        //互斥锁解决缓存击穿
/*        Shop shop = queryWithMutex(id);
        if (shop == null) {
            return Result.fail("店铺不存在");
        }*/

        //逻辑过期解决缓存击穿
       /* Shop shop = cacheClient.queryWithLogicalExpire(RedisConstants.CACHE_SHOP_KEY, id, Shop.class, this::getById, RedisConstants.CACHE_SHOP_TTL, TimeUnit.MINUTES);
        if (shop == null) {
            return Result.fail("店铺不存在");
        }*/

        //返回商铺信息
        return Result.ok(shop);
    }

/*    *//**
     * 线程池
     *//*
    private static final ExecutorService CACHE_REBUILD_EXECUTOR = Executors.newFixedThreadPool(10);

    *//**
     * 查询商铺信息，并开启逻辑过期(缓存击穿)保护
     * @param id
     * @return
     *//*
    public Shop queryWithLogicalExpire(Long id) {
        //1、从redis查询商铺缓存
        String key = RedisConstants.CACHE_SHOP_KEY + id;
        String shopJson = stringRedisTemplate.opsForValue().get(key);

        //2、判断是否存在
        if (StrUtil.isNotBlank(shopJson)) {
            //3、存在，直接返回
            return null;
        }

        //4、命中，需要先把json反序列化为对象
        RedisData redisData = JSONUtil.toBean(shopJson, RedisData.class);
        Shop shop = JSONUtil.toBean((JSONObject) redisData.getData(), Shop.class);
        LocalDateTime expireTime = redisData.getExpireTime();

        //5、判断是否过期
        if (expireTime.isAfter(LocalDateTime.now())) {
            //5.1、未过期，直接返回店铺信息
            return shop;
        }
        //5.2、过期，需要缓存重建
        //6、缓存重建
        //6.1、获取互斥锁
        String lockKey = RedisConstants.LOCK_SHOP_KEY + id;
        boolean isLock = tryLock(lockKey);
        //6.2、判断锁是否获取成功
        if (!isLock) {
            //6.3、成功，开启独立线程，实现缓存重建
            CACHE_REBUILD_EXECUTOR.submit(() -> {
                try {
                    //缓存重建
                    this.saveShop2Redis(id, RedisConstants.CACHE_SHOP_TTL);
                } catch (Exception e) {
                    throw new RuntimeException(e);
                }finally {
                    //释放锁
                    unlock(lockKey);
                }
            });
        }

        //6.4、返回过期的店铺信息
        return shop;
    }

    *//**
     * 查询商铺信息，并开启互斥锁(缓存击穿)保护
     * @param id
     * @return
     *//*
    public Shop queryWithMutex(Long id) {
        //1、从redis查询商铺缓存
        String key = RedisConstants.CACHE_SHOP_KEY + id;
        String shopJson = stringRedisTemplate.opsForValue().get(key);

        //2、判断是否存在
        if (StrUtil.isNotBlank(shopJson)) {
            //3、存在，直接返回
            return JSONUtil.toBean(shopJson, Shop.class);
        }

        //判断命中的是否是空值
        if (shopJson != null){
            //返回一个错误信息
            return null;
        }

        //4、开始实现缓存重建
        //4.1、获取互斥锁
        String lockKey = RedisConstants.LOCK_SHOP_KEY + id;
        Shop shop = null;
        try {
            boolean isLock = tryLock(lockKey);
            //4.2、判断是否获取成功
            if (!isLock) {
                //4.3、获取失败，休眠一段时间后重试
                Thread.sleep(50);
                return queryWithMutex(id); //递归调用
            }
            //4.4、获取成功，根据id查询数据库
            shop = getById(id);

            //模拟重建的延迟
            Thread.sleep(200);

            //5、不存在，返回错误结果
            if (shop == null) {
                //将空值写入redis
                stringRedisTemplate.opsForValue().set(key, null, RedisConstants.CACHE_NULL_TTL, TimeUnit.MINUTES);
                //返回错误信息
                return null;
            }

            //6、存在，将商铺信息放入redis缓存
            stringRedisTemplate.opsForValue().set(key, JSONUtil.toJsonStr(shop), RedisConstants.CACHE_SHOP_TTL, TimeUnit.MINUTES);
        } catch (InterruptedException e) {
            throw new RuntimeException(e);
        }finally {
            //7、释放互斥锁
            unlock(lockKey);
        }

        //8、返回商铺信息
        return shop;
    }

    *//**
     * 查询商铺信息，并开启缓存穿透保护
     * @param id
     * @return
     *//*
    public Shop queryWithPassThrough(Long id) {
        //1、从redis查询商铺缓存
        String key = RedisConstants.CACHE_SHOP_KEY + id;
        String shopJson = stringRedisTemplate.opsForValue().get(key);

        //2、判断是否存在
        if (StrUtil.isNotBlank(shopJson)) {
            //3、存在，直接返回
            return JSONUtil.toBean(shopJson, Shop.class);
        }

        //判断命中的是否是空值
        if (shopJson != null){
            //返回一个错误信息
            return null;
        }

        //4、不存在，根据id查询数据库
        Shop shop = getById(id);
        //5、不存在，返回错误结果
        if (shop == null) {
            //将空值写入redis
            stringRedisTemplate.opsForValue().set(key, null, RedisConstants.CACHE_NULL_TTL, TimeUnit.MINUTES);
            //返回错误信息
            return null;
        }

        //6、存在，将商铺信息放入redis缓存
        stringRedisTemplate.opsForValue().set(key, JSONUtil.toJsonStr(shop), RedisConstants.CACHE_SHOP_TTL, TimeUnit.MINUTES);

        //7、返回商铺信息
        return shop;
        }

    *//**
     * 尝试加锁
     * @param key
     * @return
     *//*
    private boolean tryLock(String key) {
        Boolean flag = stringRedisTemplate.opsForValue().setIfAbsent(key, "1", RedisConstants.LOCK_SHOP_TTL, TimeUnit.MINUTES);
        return BooleanUtil.isTrue(flag);
    }

    *//**
     * 释放锁
     * @param key
     *//*
    private void unlock(String key) {
        stringRedisTemplate.delete(key);
    }

    *//**
     * 保存商铺信息到redis缓存,并设置逻辑过期时间
     * @param id
     * @param expireSeconds
     *//*
    public void saveShop2Redis(Long id, long expireSeconds) throws InterruptedException {
        //1、查询商铺信息
        Shop shop = getById(id);

        //模拟缓存重建延迟
        Thread.sleep(200);

        //2、封装逻辑过期时间
        RedisData redisData = new RedisData();
        redisData.setData(shop);
        redisData.setExpireTime(LocalDateTime.now().plusSeconds(expireSeconds));

        //3、写入redis缓存
        stringRedisTemplate.opsForValue().set(
                RedisConstants.CACHE_SHOP_KEY + id,
                JSONUtil.toJsonStr(redisData)
        );
    }*/

    /**
     * 更新商铺信息
     * @param shop
     * @return
     */
    @Override
    @Transactional
    public Result update(Shop shop) {
        Long id = shop.getId();
        if (id == null) {
            return Result.fail("商铺id不能为空");
        }
        //1、更新数据库
        updateById(shop);
        //2、删除缓存
        stringRedisTemplate.delete(RedisConstants.CACHE_SHOP_KEY + id);
        //3、返回结果
        return Result.ok();
    }

    /**
     * 根据商铺类型分页查询商铺信息
     * @param typeId
     * @param current
     * @param x
     * @param y
     * @return
     */
    @Override
    public Result queryShopByType(Integer typeId, Integer current, Double x, Double y) {
        //1、判断是否需要根据坐标查询
        if (x == null || y== null) {
            //不需要坐标查询，根据数据库查询
            Page<Shop> page = query().eq(RedisConstants.TYPE_ID, typeId)
                    .page(new Page<>(current, SystemConstants.DEFAULT_PAGE_SIZE));
            //返回数据
            return Result.ok(page.getRecords());
        }

        //2、计算分页参数
        int from = (current - 1) * SystemConstants.DEFAULT_PAGE_SIZE;
        int end = current * SystemConstants.DEFAULT_PAGE_SIZE;

        //3、查询redis，按照距离排序、分页，结果：shopId diatance
        String key = RedisConstants.SHOP_GEO_KEY + typeId;
        GeoResults<RedisGeoCommands.GeoLocation<String>> results = stringRedisTemplate.opsForGeo()
                .search(key,
                        GeoReference.fromCoordinate(x, y),
                        new Distance(5000),
                        RedisGeoCommands.GeoSearchCommandArgs
                                .newGeoSearchArgs()
                                .includeDistance()
                                .limit(end)
                );

        //4、解析出id
        if (results == null) {
            return Result.ok(Collections.emptyList());
        }
        List<GeoResult<RedisGeoCommands.GeoLocation<String>>> list = results.getContent();
        if (list.size() <= from) {
            //没有下一页
            return Result.ok(Collections.emptyList());
        }
        //4.1、截取from = end部分
        List<Long> ids = new ArrayList<>(list.size());
        Map<String ,Distance> distanceMap = new HashMap<>(list.size());
        list.stream().skip(from).forEach(result -> {
            //4.2、获取店铺id
            String shopIdStr = result.getContent().getName();
            ids.add(Long.valueOf(shopIdStr));
            //4.3、获取距离
            Distance distance = result.getDistance();
            distanceMap.put(shopIdStr,distance);
        });

        //5、根据id查询shop
        String idStr = StrUtil.join(",", ids);
        List<Shop> shops = query().in("id", ids).last("ORDER BY FIELD(id," + idStr + ")").list();
        for (Shop shop : shops) {
            shop.setDistance(distanceMap.get(shop.getId().toString()).getValue());
        }

        //6、返回
        return Result.ok(shops);
    }
}
